The present claimed invention relates to stress measurement method especially preferably used for measuring stress of a measurement specimen whose shape and composition are standardized to a certain degree such as a mass-produced semiconductor substrate and devices.
In order to measure stress applying to a specimen in a process line, it is required to measure the specimen nondestructively in a short period of time. Furthermore, in a field of, for example, semiconductor manufacturing, recently a request has been arising for measuring stress applying to micro-structures smaller than μm order or thin films accurately.
As a method for measuring stress applying to a specimen, there are the XRD (the X-ray Diffraction) and the CBED (the Convergent Beam Electron Diffraction) as shown in the patent document 1 or the patent document 2.
In accordance with the XRD, the stress can be measured without destroying the specimen. However, since the XRD has a spatial resolution of several dozen μm at most, it is difficult to measure the stress applying to a micro-structure of smaller than a μm order or a thin film accurately. Furthermore, there is a problem that it takes time to measure the stress.
In accordance with the CBED, the stress can be measured accurately by making use of a very high special resolution of smaller than 100 nm. However, since a broken measurement specimen has to be prepared separately, there are some problems such that it takes time to conduct measurement and the measurement specimen does not coincide with an actually manufactured device in a precise sense.
Accordingly, if the above-mentioned XRD or CBED is actually applied to measurement of stress in a process line, the time required for measurement becomes a big bottleneck.
On the contrary, as shown in the patent document 3, if the Raman spectroscopy is used, it becomes possible to conduct measurement in a short period of time to a degree applicable for a process line. With this method, however, a measurable area by using a microscope is about 1 μm at the minimum and an area smaller than 1 μm is difficult to measure.
More specifically, in order to measure the stress applied to a micro-structure of smaller than a μm order or a thin film, either conventional method would produce some problem in a point such as a size of a measurable area, time required for measurement, nondestructive measurement or a measurement accuracy.
Patent document 1 Japan patent laid-open number He1-219529
Patent document 2 Japan patent laid-open number 2000-009664
Patent document 3 Japan patent laid-open number 2006-73866